Illinois American Annual Water System Treatment – August 26, 2020

O’Fallon, Illinois – Illinois American Water will begin the annual maintenance of their water system on August 26, 2020. Illinois American Water’s water quality team will be switching treatment to a form of chlorine known as “free chlorine,” which does not contain ammonia. The City of O’Fallon will be notified when they go back to the normal type of disinfectant in approximately two months.

The safety of the water will not be affected by this temporary change. Many water plants use chlorine in the free, uncombined form on a regular basis. Illinois American Water will continue to supply high-quality water that meets the requirements of the Illinois Environmental Protection Agency. There is no need to boil the water. If an objectionable difference in odor is noticed, please allow the water drawn from the tap to sit in a refrigerator for a few hours.

Dialysis patients and renal care facilities should be aware of these changes and adjust their health care practices accordingly.

This change is needed to remove residues that have been collected due to their normal disinfection practices.  Water leaving the plant is usually disinfected with a combination of chlorine and ammonia.  Combining the chlorine with ammonia is beneficial in that it prevents bacterial growth by keeping the chlorine in the water longer.  It also prevents disinfection by-product formation and taste / odor problems.  The use of the ammonia with the chlorine, however, can result in a buildup of amounts of certain chemicals.  These chemicals can be removed or prevented from forming by using free chlorine rather than the combined chlorine for a short time each year. 

The City of O’Fallon buys treated water wholesale from the private company, Illinois American Water, and then pumps it to all water customers. Therefore, Illinois American Water will be treating the water prior to its delivery to the City of O’Fallon’s pumping station in French Village.

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If you would like more information about this topic, please contact Grant Litteken at 618-624-4500 x 8760 or email at [email protected].